Refactor command dispatch.
Ask for additional parameters instead of complaining.
Merge pull request #13 from kaos/kaos

Refactor command dispatch and parameter handling by @kaos

* Refactor command dispatch
* Ask for additional parameters instead of complaining
Update src/erltrek_phaser.erl

* Remove a case expression supressing the notification
  See
  https://github.com/jj1bdx/erltrek/commit/2972a8e0a9dc4815c46a2ae507bec8141d426c4f#commitcomment-5722382
Update erltrek_phaser.erl

* Change hitting level calculation to cause wider range of damage even if not accurately on the firing track